Cell Biology

Question 1

What is mean division time ?

Answer 1

Time taken for one bacterial cell to divide into two.

Question 2

Name two factors effecting the rate of binary fission

Answer 2

Warm environment and lots of nutrients

Question 3

What type of cell does binary fission occur in ?

Answer 3

Prokaryotic cells

Question 4

What do bacteria have instead of a nucleus

Answer 4

Singular strand of circular DNA

Question 5

What is the formula for magnification ?

Answer 5

Image size x real size

Question 6

What is the name of the large adjustment knob on a light microscope ?

Answer 6

Coarse adjustment knob

Question 7

What is the name of the smaller adjustment knob on a light microscope ?

Answer 7

Fine adjustment knob

Question 8

Define differentiation

Answer 8

The process in which a cell changes to perform a specific function

Question 9

How is a sperm cell specialised ?

Answer 9

Long tail, streamline shape, lots of mitochondria, and enzymes in the head to break down the egg membrane

Question 10

How are nerve cells specialised?

Answer 10

Long, have branched connections

Question 11

How are muscle cells specialised?

Answer 11

Long and contain lots of mitochondria

Question 12

How are phloem and xylem specialised?

Answer 12

Xylem are hollow, phloem have very few sub-cellular structures to allow flow through them

Question 13

What is the first stage of the cell cycle?

Answer 13

Strands of DNA in the nucleus replicate to form two pairs of each chromosome

Question 14

What is the second stage of the cell cycle ?

Answer 14

The nuclear membrane breaks down, the chromosomes line up in the centre of the cell

Question 15

What is the third stage of the cell cycle ?

Answer 15

One set of each chromosome is pulled to each end of the cell and the nucleus divides

Question 16

What is the final stage of the cell cycle?

Answer 16

The cytoplasm and cell membranes divide to form two identical cells

Question 17

What is binary fission?

Answer 17

It is the process in which bacteria replicate itself

Question 18

What parts of the prokaryotic cell replicate in binary fission?

Answer 18

The circular DNA and the plasmids are replicated

Question 19

What is agar jelly?

Answer 19

Agar jelly is a nutrient broth solution used for growing bacteria

Question 20

Why can you not grow bacteria above 25°C in school?

Answer 20

Above 25°C there can be harmful pathogens produced

Question 21

What is the inhibition zone?

Answer 21

The inhibition zone is the area around a paper disk soaked in an antibiotic that no bacteria have grown in

Question 22

What is the control when investigating the effects of antibiotics on bacteria?

Answer 22

Make sure you use two disks that have no antibiotics on to prove that the paper has no correlation with results

Question 23

How would you sterilise an inoculating loop and Petre dish ?

Answer 23

You would heat up the inoculating loop and tape on the petre dish lid to prevent bacteria from affecting results

Question 24

What does it mean if there is a larger inhibition zone around a paper disk soaked in antibiotics than another ?

Answer 24

It shows that one antibiotic is more effective against the bacteria than another

Question 25

Why are embryonic stem cells unique ?

Answer 25

They can turn into any type of specialised cell

Question 26

What is therapeutic cloning?

Answer 26

Where an embryo can be made to have the same genetic information as the patient and so stem cells produced from it wouldn’t be rejected by the patients body

Question 27

What is a risk of stem cells?

Answer 27

If they are contaminated with a virus when in the lab they could make a patient sicker

Question 28

Where are stem cells found in plants ?

Answer 28

They are found in meristems

Question 29

What can stem cells from a plant do ?

Answer 29

Produce identical copies of whole plants quickly and cheaply, can also produce plants with desired features such as disease resistant

Question 30

What is active transport?

Answer 30

Active transport is when a substance moves from a lower to a higher concentration

Question 31

How are root hair cells specialised?

Answer 31

They have millions of tiny hairs on them which gives them a large surface area for absorbing water and mineral ions

Question 32

How is active transport different from diffusion ?

Answer 32

Active transport goes from low to high concentration, requires energy from respiration

Question 33

Where and how is active transport used in humans ?

Answer 33

It is used in the gut to transfer a higher concentration of nutrients in the blood than in the gut

Question 34

What factor affects how easy it is for an organism to exchange substances with its environment?

Answer 34

The organisms SA : Vol

Question 35

Why is it easier for single celled organisms to exchange substances in or out of the cell?

Answer 35

As the cell is smaller it has a higher SA : Vol

Question 36

Why do multicellular organisms need an exchange surface?

Answer 36

They have a smaller SA : Vol so not enough substances can diffuse from their outside surface to supply their entire volume. This means an exchange surface is required for efficient diffusion

Question 37

How are exchange surfaces adapted ? Why?

Answer 37

They have a thin membrane so substances only have a short distance to diffuse, large surface area so lots of substances can diffuse at once, in animals there are lots of blood vessels to get substances in and out of the blood quickly

Question 38

How are alveoli specialised ?

Answer 38

An enormous surface area, moist lining for dissolving gases, very thin walls, good blood supply

Question 39

How are villi in the small intestine specialised ?

Answer 39

Increases surface area for faster rate of digestion, single layer of surface cells, good blood supply for quick absorption

Question 40

What do stomata do ?

Answer 40

Stomata are what carbon dioxide diffuses through and how water vapour is let out of the leaves

Question 41

What do guard cells do ?

Answer 41

Guard cells close the stomata if the plant is losing water faster than it can be replaced by the roots

Question 42

Where are the exchange surfaces on a leaf?

Answer 42

The underneath and the walls of the cells inside

Question 43

How are cells in leaves an effective exchange surface ?

Answer 43

The air gaps around them increase their surface area so there is more chance for carbon to get into cells

Question 44

What are gills used for in fish?

Answer 44

Gills are used as a gas exchange surface in fish

Question 45

How do gills work?

Answer 45

Water containing oxygen passes through the gills and oxygen diffuses from the water to the blood in the gills and the carbon dioxide diffuses from the blood to the water

Question 46

How are gills specialised for gas exchange ?

Answer 46

Lots of thin plates called gill filaments have a big surface area for gas exchange, lamellae on the gill filaments increase surface area even more and have lot of capillaries to speed up diffusion, thin surface layer of cells, water flows one way and blood flows the other which maintains a large concentration gradient